Abstract 1269: Evaluating the effect of metformin on components of extracellular matrix in colorectal cancer

Abstract

Abstract Introduction: Colorectal cancer (CRC) is the third most common cancer worldwide, and is associated with high morbidity and mortality. Approximately 50% of all CRC patients develop metastases. Tumor microenvironment (TME), including extracellular matrix (ECM), plays an important role in tumor progression and metastasis in CRC, indicating an important role of agents targeting ECM in the treatment of CRC. ECM acts as niche to support cancer cells. In this study, the role of metformin as a therapeutic agent in modulating ECM components of CRC has been studied. Methods: HCT116 (aggressive, poorly differentiated) and HT 29 (less aggressive, moderately differentiated), human CRC cell lines were treated with different doses of metformin (0.1, 2.5 and 5 mM) for 14 days in vitro and subsequently microarray analysis was done to identify differentially expressed genes. To observe the role of metformin in modulating the ECM, ECM-receptor interaction pathway was given primary focus among the list of pathways identified by DAVID (Database for Annotation, Visualization and Integrated Discovery) bioinformatics resources. The seven differentially expressed genes of ECM-receptor interaction pathway (elucidated by microarray) were -COL3A1, COL4A2, COL5A2, VTN, ITGA6, TNXB and LAMC3. These genes were validated using RT-qPCR in both the cell lines. Protein expression was analyzed by Western blotting. Immunohistochemistry (IHC) was done in different histopathological grades of CRC samples to evaluate the expression and localization of ECM proteins. Results: The gene expression of COL4A2, COL5A2, ITGA6, VTN and TNXB by RT-qPCR was decreased with metformin treatment and these results were consistent with microarray data. However, discrepancy was observed in the gene expression of COL3A1 and LAMC3 between microarray and RT-qPCR. Expression of COL3A1, VTN was found to be increased whereas a decrease in expression of ITGA6 was observed in different histopathological grades of CRC samples with IHC. The expression of PI3K and AKT proteins were decreased in HCT116 cells with metformin treatment justifying its anticancer properties. Conclusions: Anticancer role of metformin via mTOR and PI3K-AKT signaling has been studied before, but this study identifies the novel ECM proteins in CRC that can be modulated by metformin. The results from this study indicates the promising role of metformin in CRC as it is associated with very less side effects and can influence various aspects of cancer biology. Citation Format: Amar Preet Kaur, Aditi Bhattacharya, Muzaffer Ahmed Bhat, Aakriti Bansal, Sudip Sen. Evaluating the effect of metformin on components of extracellular matrix in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1269.